author=Jpratt
Point at things.
Jump in dumpster.
Be shocked by presents.

Seriously though I assume J is jump. If so it would be more intuitive to have it as the bottom button on a controller rather than the left button.

Yep J is jump. WASD is move and L is interact.

The reasoning for the buttons is due to some advanced controls not pictured. K or the Bottom Button on a controller is a Dash button, and speed effects jump distance.

So the controller you can use your thumb to hold Run and also tap Jump.
Or on keyboard hold K with your middle finger and tap J with your index finger.